If You need an empty inline span (-s) to have a width and height (for background image or something else) then there is a fix for that.

Each application has 2 bars at the top: status bar and title bar. Sometimes it's useful to remove/hide them (especially in gaming apps).

Sometimes we need to have a static top and bottom with the rest space taken by the main content.

html {overflow-y: scroll !important;}

To submit a form using POST method through PHP, just add the data to be posted as header. This essentially saves one extra html page sent to the browser when user has to be redirected. Mostly found this technique useful for redirecting to payment gateways.